Personal computer systems are well known in the art. Personal computer systems in general, and IBM Personal Computers in particular, have attained widespread use for providing computer power to many segments of today's modern society. These systems are designed primarily to give independent computer power to a single user and are inexpensively priced for purchase by individuals or small businesses. Personal computer can typically be defined as desktop, floor standing, or portable computers that consist of a system unit having a single central processing unit (CPU) and associated volatile and non-volatile memory, including RAM and BIOS ROM.
One of the distinguishing characteristics of these systems is the use of a motherboard to electrically connect these components together and to provide for adapter or expansion cards to be added to the motherboard to perform any of a wide variety of functions. These functions may be options which a user may select at the time of ordering the computer and which are installed prior to the user installing the computer, or they may be chosen by the user to add to his existing computer. Examples of the functions performed by adapter cards include additional video cards to provide enhanced video output to a system monitor, audio cards to provide for recordal, playback and editing of data relating to audio, communication cards such as a modem card or a Local Area Network card to allow communication with other computers over a network, or a fax card to allow fax transmissions to be sent and received. Additionally, such adapter cards may provide for more memory to be added to an existing computer than can be added to the motherboard. A system typically also includes a system monitor, a keyboard, one or more flexible diskette drives, a fixed disk storage drive (also known as a "hard drive"), a so-called "mouse" pointing device, and an optional printer.
Adapter cards consist of a printed circuit board with electronic components mounted on the circuit board, a number of contact strips provided along an edge of the circuit board which are intended to plug into a connector of the corresponding type on the motherboard, and a plate-shaped mounting bracket at one end of the circuit board to provide mechanical fixing of the card to the computer system and also to provide for the positioning of connectors to allow connections to external devices to be made.
In many computers, the insertion or the removal of an adapter card requires that the power to the computer be turned off prior to insertion or removal of an adapter card. In more recent systems, adapter cards can be inserted into and removed from the computer while the system still has power applied. The insertion or removal operation whilst power is still applied is called "hot-plugging".
Since many adapter cards have a plate-shaped mounting bracket at one end of the circuit board and because, in a "hot-plug" computer, the computer still has power applied during insertion or removal of an adapter card, accidental contact between the mounting bracket and components on the motherboard may cause an electrical short circuit. Similarly, accidental contact between the mounting bracket or other conductive parts of the adapter card and adjacent adapter cards may also cause an electrical short circuit.
Existing solutions to this problem include the attachment of rigid dividers to the computer chassis rather than to the card itself. These rigid dividers must be removed before the motherboard itself can be removed. These rigid dividers and their corresponding mountings are also expensive. Another solution is the use of a substantially rectangular card insulator positioned between two adjacent adapter cards. The card insulator is attached to a motherboard insulator, which is a large sheet of semi-rigid or rigid plastic covering the entire motherboard.
So it would be desirable to provide a solution which did not require a large insulator over the entire motherboard and which did not require the use of large rigid insulators associated with each of the adapter cards.